Regeneration of spent catalyst



REGENERATON. OF SPENT CA'IIALYS'II ARCH L. FOSTER BY 'wf fa?? A TTORNEYSFeb. 18, 1947. A. FosTER REGENERATION OF SPENT GATALYST Filed Oct. 5,1942 2 Sheets-Sheerl 2 Patented Feb. 18, 1947 AUNITED sTATEs PATENTOFFICE REGENERATION F SPENT CA'IIALYST Arch L. Foster, Bartlesville,Okla., assignor to Phillips Petroleum Company, a corporation of DelawareApplication October 5, 1942, Serial No. 460,877

number of hydrocarbon reactions and conversions may be carried out inthe presence of various types of catalysts. It has been discoveredcomparatively recently that metal halide catalysts may be advantageouslyutilized in carrying out certain hydrocarbon conversions. Aluminumchloride has been found to be among the more important catalysts in thisgroup. One of the major problems encountered in the industry has beenthat of regenerating metal halide catalysts 3 Claims. (Cl. 23-96) tothereby recondition the same in order that they may be reusedeffectively. In the course of carrying out the hydrocarbon processes,referred to above, in the presence of metal halide cata` lysts, thecatalysts become degraded and substantially spent as they eventuallybecome coated with heavy hydrocarbon materials. Considerable diicultyhas been encountered in reconditioning these catalysts. Metal halidecatalysts such as aluminum chloride, due to their volatility, cannot, asa rule, be regenerated by the usual methods employed in regeneratingnonvolatile catalysts. Material, such as sludges, carbon, and the like,that blankets these catalysts cannot be removed by the oxidation of thesame at temperatures in the region of 1200 F. and higher, since thecatalyst itself will become decomposed and volatilized at suchtemperatures under normal pressure conditions. This results in the lossof valuable constituents. Another difficulty usually encountered residesin the fact that sludges formed with metal halide catalysts combinechemically to a greater or lesser degree with the catalyst and cannot beseparated therefrom by purely mechanical means in their original statewhen the catalyst mass is subjected to a reactivating treatment. ItWill, hence, be evident that it is extremely essential that proper stepsbe taken to remove sludge, including carbonaceous material from thespent catalyst, in such a manner that the catalyst may be recovered in asubstantially pure state.

My present invention contemplates the regeneration of degraded metalhalide catalysts by the use of hydrogen, which may be either puremolecular hydrogen or a free hydrogen-containing gas that is composed ofhydrogen and one or more other constituents that are basically inertwhen employed in the practice of my invention, such as light hydrocarbongas, iiue gas, nitrogen, deoxygenated air, or the like. TemperaturesWithin the range of 500 to 1200 F. and up may be employed, and ingeneral, the pressures attained in the practice of my invention rangefrom 100 to 1000 pounds per square inch. In order to 1 secure optimumrecovery of the metal halide catalyst, the pressure should at all timesbe maintained suiiiciently high so that none of the catalysts will bevolatilized, and thereby lost during the regeneration procedure. Spentcatalysts employed in relatively low temperature processes are usuallyuid, and are relatively high in hydrogen to carbon ratio. For thesecatalysts the temperatures, pressures and reaction times arecomparatively lower than the corresponding temperatures, pressures andreaction times that are necessary to regenerate spent catalysts obtainedfrom high-temperature and long time reaction processes. The spentcatalysts from the latter` type of processes are generally solid inconsistency and high in carbon content.

The instant invention is applicable to the regeneration of spent ordegraded metal halide catalysts that may be either in a solid or fluidstate. My invention teaches the regeneration of solid catalysts in situ,and the regeneration of fluid or semi-fluid catalysts, such as sludgesof the same, by the mixture thereof with a hydrocatalyst that is alsopreferably fluid, such as a slurry, before regeneration. The spentcatalyst, Whether in a solid or a fluid state is brought into intimatecontact with free hydrogen and the hydrocatalyst under temperature andpressure conditions that will result in effective hydrogenation of thespent catalystr without the loss of the metal halide catalyst byvolatilization. The hydrocat- .alyst mentioned above may include anyWell known catalyst in the art that is adapted to promote hydrogenationof the spent catalyst.

For example, the hydrocatalyst may be any one of the known catalysts,including metal oxides, suldes, or the like. While the hydrocatalystsmay be used in any desired form, I prefer to use the same in a finelydivided or pulverulent condition in order that it may be readilysuspended in a suitable hydrocarbon which acts as a solvent or diluentfor the relatively heavy oils formed -from the spent catalyst sludge inthe course lof hydrogenation.` Wherever the term, hydrocatalyst slurry,appears in this specification, it will be understood that the samerefers to a uid mixture comprising a hydrocatalyst and a relativelylight hydrocarbon or other liquid, capable of being advantageouslyemployed with my invention. In this connection it is recommended thatthe hydrocatalyst slurry employed be such that it will not dissolveappreciable amounts of the metal halide catalysts. Sludge solvents suchas those disclosed in my copending application, Serial No. 459,579, ledon September 24, 1942, are satisfactory for use with my invention. Ithas also been found that low viscosity oils, such as light gas oil,solar oil, numeral seal oil,

or a similar oil of low volatility and low residual.

carbon content and substantially free of solid, asphaltic, or bituminousmaterial, is also satisfactory.

This invention has for its primary object the removal of carbonaceousmaterial, such as hydrocarbon sludge, from spent catalysts.

. ,Another object of this invention is the removal of carbonaceousmaterial from spent metal halide catalysts in such a manner as willleave the catalyst in a substantially completely revivied condition,with the greater portion of its original activity as a catalyst restoredfor reuse.

A further object of this invention is the regenerationV of degradedcatalysts by the hydrogenation thereof, either in the presence of or inthe absence of a hydrogenation catalyst.

This invention has for another object therevivication of a volatilecatalyst, such as aluminum. chloride, by changing its chemical conditionin a sludge containing the samek so that it may be readily separatedfrom the sludge and recoveredior reuse.

A still further object of this; invention isY the regeneration of spentmetal halide catalysts that are. containedin hydrocarbon sludges of thesame, and the recovery oi hydrocarbon material from the sludge` as auseful commercial product or a crude material that is convertible into.one or ,more useful commercial products.

These, as well as other objects and advantages, will be readily apparentto persons skilled in the art from the following detailed descriptionand the annexed. drawingsV which respectively describe and, illustratepreferred arrangements of apparatus for carrying. out the invention.

"Figure 1 is a schmatic representationof apparatus for`V use inregenerating spent solidv metal halide catalysts in accordance with myinvention.

Figure 2 isa schematic representation of apparatus for use inregenerating spent fluid or semi-fluid metal halide catalysts inaccordance with my invention.

Referring now to the drawings, and more particularly to Figure '1.thereof, I have denoted therein a conduit I through which a freelhydrogen-containing gas of the character indicated earlier, istransmittedinto a preheater I IA, wherein the same is heated to atemperature preferably between 300 and 1000 Fgand is then transmittedthrough a conduit I2` into the lower portion4 of a chamber I3 under apressure up to about 1000 pounds per square inch gauge. Chamber f3contains a quantity of solid degraded metal halide catalyst, such asspent aluminum chloride. The degraded catalyst is placed in chamber I3through a charging means 4Q and is withdrawn therefrom afterregeneration through a discharge means 45. The degraded or spentcatalyst may be one obtained from a hydrocarbon conversion process, andcontains hydrocarbon material. A hydrocatalyst slurry in conduit I4 ispreheated 4 in a unit I5 and then transmitted through line It into theupper portion of chamber I3. It is recommended that the hydrocatalystslurry contain from 5 to 50% of the hydrocatalyst material insuspension, the percentage of this material depending upon the porosityof the degraded metal halide catalyst,4 its refractoriness, and itsgeneral condition. Thel degraded catalyst in chamber I3 is heated by anelement I'I disposed therein to a temperature whereby the degradedmaterial may be properly and eiectively hydrogenated. The amounts offree hydrogen-containing gas and hydrocatalyst slurry admitted intochamber I3 are preferably such as will result in the optimum rate ofhydrogenation ci degraded metal halide catalysts in said chamber. t willbe obvious that these rates will vary, depending upon various factors.It will be equally obvious that the proper rates may be readilydetermined by persons skilled in the art in each particular case, forexample, by trial. For best results the amount of free hydrogen that iscirculated through the degraded catalyst in chamber I3 should at alltimes be greatly in excess or that required for carrying out thehydrogenation procedure. It is preferred that not more than about of thehydrogen admitted into chamber I3 be consumed during a single passagethrough the degraded bed. Unconsumed hydrogen is withdrawn as anoverhead product from the top of chamber I3 and is recycled through aconduit I8 to conduit I0. In the course of the hydrogenation of thematerial in chamber i3, hydrocarbons and other carbonaceous materialscontained in the degraded catalyst are converted into fluidhydrocarbons, such as oils; and the oil thus formed, together withhydrocatalyst slurry is discharged from the bottom of chamber I3 throughline I9 and thence through branch lines 20 and 2ly into a pair offilters 23 and 24, respectively. Hydrocatalyst material in a solid stateis removed from the mixture introduced into filters 23 and 24 and iscontinuously or periodically unloaded bymeans of conveyer lines 2E' and21, which connect with a main conveyer line 28 that communicates with ahydrocatalyst regenerator unit 29. Free oxygen-containing gas for use inthe regeneration of the hydrocatalyst in unit 29 is supplied by aconduit 30, and the products of combustion, such as carbon dioxide,carbon monoxide, as welll as unconsumedv oxygen, are discharged fromregenerator 29 by way of line. 3I. Substantially pure reviviedhydrocatalyst is carried by a Suitable conveyer 32 into a storagereceptacle, or the like, 33. The oil and other fluid material that isseparated in filters 23 and 24 are. discharged therefrom through branchconduits 34 and 35', respectively, which communicate with a maindischarge line 38 that communicates withy a fractionator or similarseparator unit 31. The material thus admitted into a fractionator 31 isseparatedk in the usual manner, the oil being withdrawn through aconduit 38 and the remainder of the fluid in the'nature of a diluentbeing withdrawn through a conduit 39; The diluent from conduit 39 andnecessary makeup diluent supplied. by a conduit 49 are introducedthrough a line 4I into a mixer 42, wherein it is mixed with solidhydrocatalyst that is transmitted thereto by means of a conveyer 43 toform hydrocatalyst slurry for passage through conduit I4; The abovedescribed. cycle is then repeated.

Turning next tothe arrangement-'of appa@ ratus illustrated in Figure 2of the drawings,

variete-i9 '5 reference numeral U indicates a conduit through whichdegraded metal halide catalyst of the char- ,acter indicated above butin av fluid or sludge condition, and a suitable `diluent ina conduit 5|are combined in aline 52 that communicates with va conduit 53. Asisevident from-Figure 2 this said diluent is the same diluent that isused to 4make up the hydrocatalyst slurry and is ,recycled .continuouslythroughout the process, as shown.

As previously indicated the diluent is preferably Aa non-solvent forboth hydrocatalyst and the metal halide catalyst to be regenerated andacts merely as a diluent for the sludge or a suspending medium for thehydrogenating catalyst. A line 55 for transmitting hydrocatalyst slurryalso communicates with conduit 53. The materials transmitted intoconduit 53 by the above mentioned conduits and lines are forced by apump 55 into a mixer 53.. It is recommended that the proportions ofhydrocatalyst slurry tometal halide catalyst sludge be between theratios of 5:1 and 1:10 for best results. After being thoroughly agitatedin mixer 56, the composite material contained y therein is transmittedby a conduit 51 into the upper portion of a hydrogenating unit 58. Freehydrogen-containing gas supplied by a conduit 5S is preheated ina unit60 and is then transmitted into hydrogenating unit 58. Hydrogenating`unit 58 operates in a manner similar to that discussed with regard tochamber I3 in Figure 1. It will be evidentV that this unit may consistof a single chamber, as illustrated, or of several chambers,` in aseries or in paralleLthe number and arrangement of the same depending onthe character of the metal halide catalyst sludge to be treated.Unconsumed hydrogen is taken off the top of unit 58 and may be recycledto conduit 59 if desired. The hydrogenated slurry is removed from unit58 through aline 63, either continuously or intermittently, and is takento a filter or settler 64. The material withdrawn from chamber 58comprises hydrocarbons, solid hydrogenating catalyst and solid metalhalide catalyst which has been regenerated; The metal halide catalystmay be soluble to some extent in the light hydrocarbons but since theselight hydrocarbons are continuously recycled as the diluent, as shown inFigure 2, they become saturated with said metal halide catalyst as theresult of which no further metal halide is dissolved after saturation.For this reason most of the metal halide regenerated from the sludge ispresent in the solid state in the material withdrawn from chamber 58. Amixture of hydrocarbon oil and diluent is separated from catalystmaterial in filter 64 and is discharged therefrom through a line 65which communicates with a heater 66. Heater 66 serves to preheat thismixture before it is transmitted through a conduit 61 into afractionator or other separating means 68. Fractionator 68 is operatedin the usual manner to separate the material admitted thereto intohydrocarbon oil which is removed through a conduit 69 and diluent whichis taken 01T as a top product through a conduit that communicates withconduit 5 l. The catalyst material, including both metal halide catalystand hydrocatalyst components, is transported by conveyer 1l into avaporizer 12. Air or other free oxygen-containing gas is supplied tovaporizer 12 by means of a conduit 13. Vaporizer 12 is operated underconditions whereby the metal halide component of the mixed catalyticmaterial therein is vaporized and removed therefrom through a conduit 14that communicates With a chamber 13, wherein said metal halide catalystiScQndenSed. Since thev catalyst material introduced into vaporizer 12contains oc- Vof vaporizer 12 are discharged through a conduit 15.Hydrocatalyst material is removed from vaporizer 12 by means of aconveyer 18, is regenerated in a unit 19 that is similar to thecorresponding Aequipment illustrated in Figure 1, and is thentransported by a conveyer 80 into a unit 8l, wherein it is thoroughlyagitated and mixed with' diluent that is supplied by a conduit 82, tothereby form necessary hydrocatalyst slurry that is handled by conduit54.

No attempt has been made to set forth specific conditions of temperatureand pressure under which the various items of equipment illustrated inthe drawings should be operated, since the same depend to a great extentupon the particular conditions encountered; yand further, since the samemay be readily ascertained by persons skilled in Athe art.

From the foregoing, it is believed that the many 'advantages obtainableby the practice of the present invention will be readily apparent topersons skilled in the art. However, since certain changes may be madein carrying out the above process without departing from the scope ofthe invention as defined by the appended claims, it is intended that allmatter contained herein shall be interpreted as illustrative andexplanatory, rather than in a limiting sense.

What I claim is:

1. A process for the regeneration of a metal halide catalyst that hasbecome contaminated with carbonaceous deposits in use for the conversionof hydrocarbons, which comprises the steps of admixing a hydrocarbondiluent, a hydrogenating catalyst and a sludge of a contaminated metalhalide catalyst, passing said mixture into a regenerating zone, passinga free hydrogencontaining gas through said mixture in said zone,maintaining a temperature between about 500 F. and about 1000 F. and asuperatmospheric pressure suiiiciently high to prevent volatilization ofany metal halide catalyst in said zone, discharging unconsumed hydrogenfrom said Zone, removing a resulting mixture comprising hydrogenatingcatalyst, hydrocarbons and a solid metal halide catalyst from saidregenerating zone, separating said hydrocarbons from said hydrogenatingand said metal halide catalysts by filtration, fractionating saidseparated hydrocarbons and recycling the overhead of said fractionationas a diluent, passing said hydrogenating and metal halide catalysts to avaporizing zone, va-

porizing said metal halide catalyst and removing same as an overheadproduct therefrom for recovery, and removing said hydrogenating catalystas a bottom product from said vaporizing zone.

2. An improved process for recovering aluminum chloride from a liquidhydrocarbon-aluaereo@ minum chloride sludge, whichv comprises.intimately admixing with said liquid sludge a nely divided' solid-metaloxide hydrogenation catalyst with a ratio of said catalyst tosaid sludgebetween l5:1 and 1:10 and a low-boiling liquid hydrocarbon solvent,treating said mixture at a hydrogenation temperature between 500 and1200 F. with free hydrogen at a pressure of 1010 to 1000 pounds persquare inch and eiect'ing a hydrogenatio-n of said sludge and a releaseof free aluminum chloride, removing resulting mixed solid aluminumchloride and hydrogenation catalyst from a liquid hydrocarbon material,distilling' said material to produce a low-boiling hydrocarbon fractionand high-boiling hydrocarbon fraction, returning said 10W-boilingfraction to said hydrogenation as said solvent, treating said mixedsolid materials with oxygen under conditions such as to vaporizealuminum chloride and to burn carbonaceous material, separating vaporsso produced from residual solid metal oxide, recovering aluminumchloride from said vapors, and'returning said metal oxide to saidhydrogenation.

3. An improved process for recovering a solid volatile metal halidecatalyst from a liquid hydrocarbon-solid metal halide sludge', whichcornprises intimately admixing with said liquid sludge a nely dividedsolid metal oxide hydrogenation catalyst with a ratio of said catalystto said sludge between 5:1 and 1:-10 and a low-boiling liquidhydrocarbon solvent, treating said mixture at a hydrogenationtemperature between 500 and 1200D F. with freehydrogen at a pressure of100 to 1000 pounds per square inch and eectng a hydrogenation. of saidsludge and a release of free solid' metal halide, removing resultingmixedv solid' metal halide and hydrogenation catalyst from a liquidhydrocarbon material, distilling said material to produce a low-boilinghydrocarbon fraction and high-boiling hydrocarbon fraction, returningsaid lowboiling fraction to said hydrogenation as said solvent, treatingsaid mixed solid materials with oxygen under conditions such as tovaporize said metal halide and to burn carbonaceous material, separatingvapors so-produced from residual solid metal oxide, recovering saidmetal halide from said vapors, and returning said metal oxide to saidhydrogenation.

ARCH L. FOSTER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PA'I'ENTS British Jan. 22, 1923

